A related case (Number C-1509) has described the preparation of a new family of polymer complexes based on the interaction of a sulfonate ionomer and a second polymer containing basic amine groups. The resulting complex has been shown to be extremely effective in enhancing the viscosity of organic solvents, fuels, and lubricants. Furthermore, it has been shown that the high viscosity of such fluids containing these complexes can be reduced by the addition of suitable polar cosolvents at a level of from 1/2% up to 10% or more. The instant invention differs markedly from the cited case in that the addition of polar cosolvents can act to increase the viscosity of polymer complex thickener organic at extremely low levels of added cosolvent, for example, as low as one part of alcohol per 1,000,000 parts of organic fluid.
There are cases of prior art dealing with ionic polymers in hydrocarbon. The comments below deal with specific prior art.
U.S. Pat. No. 3,396,136 describes how copolymers of alkenyl aromatic sulfonic acids, when properly neutralized, can be employed as thickeners for nonpolar solvents. Those metal sulfonate systems have been shown to be very effective; however, when employed as two component systems (i.e., ionic polymer plus nonpolar solvent), the variation of viscosity with increased temperature is very conventional and predictable. That is, the solution viscosity decreases markedly as temperature is increased.
U.S. Pat. No. 3,396,136 further teaches "in situ" neutralization of the sulfonic acid polymer which, under some conditions, can result in the availability of a small amount of polar cosolvent. In addition, the cited patent is restricted to aromatic sulfonate polymers. The instant invention is concerned with the addition of very small amounts of cosolvents to polymer complexes as described below. The addition of such small amounts of cosolvents to simple solutions of sulfonate ionomers alone has no significant effect on the viscosity.
U.S. Pat. No. 3,366,430 teaches the gelling of organic liquids by the interaction of polar "associative bonds" which includes hydrogen bonding and "ionic cross-linking". Again, this patent specifies that two components are necessary--the associating polymer (or polymers in some cases) and the nonpolar organic liquid. There is no mention of a third polar cosolvent except to point out that such polar liquids should not be present. Specifically, this patent states (Column 2, line 7) that the hydrocarbon liquids to which this invention is to be applied should not contain a substantial portion of a miscible protolytic liquid such as methanol. It is clear that the language of this patent limits this invention to gels and further, that any amount of polar liquids which are present to an extent where they disrupt those gels are undesirable. The instant invention is distinct from that cited in that amounts of such polar compounds, as will break up gel at ambient conditions, are required and in fact the most preferred state is free of any said gel at ambient temperatures.
U.S. Pat. No. 3,679,382 teaches the thickening of aliphatic hydrocarbons with synthetic organic polymers which contain olefinically unsaturated copolymerizable acids, amides, hydroxyacrylic esters, sulfonic acids, etc. It is emphasized in this patent (Column 3, line 72) that it is critical that in the preparation of such polymers, no surface active agent, catalyst or other additive be employed which introduces a metallic ion into the system. Therefore, it is preferred to employ ammonium or amine salts. It is clear that this invention (U.S. Pat. No. 3,679,382) specifically precludes the use of metallic counterions--and is directed towards amine or ammonium derivatives. Only metallic counterions are effective in the instant invention--and that, in fact, attempts to employ amine derivatives have not resulted in the results which are the objectives of this invention. Finally, this cited patent does describe (Column 7, lines 13-19) that the addition of alcohols will reduce the viscosity of the thickened hydrocarbon and alter flow characteristics thereof.
U.S. Pat. Nos. 3,931,021 and 4,118,361 describe the use of ionic polymers and required cosolvents in an organic liquid and V.I. Improvers. The instant invention represents an improvement over U.S. Pat. Nos. 3,931,021 and 4,118,361 because in those patents the use of cosolvent reduced the viscosity of such solutions at levels .gtoreq.0.1% by volume and had little effect at lower levels. The instant invention describes the effect of much less cosolvent (by as much as 1000.times. less) acts to increase the viscosity of an organic fluid containing a suitable polymer complex. Clearly the complex is much different from the ionomers described in the cited patents.